The present invention relates to lifting mechanisms and, more particularly, to a lifting device which is adapted to elevate the revolving frame of a heavy mechanical shovel from its wheeled undercarriage.
Heavy vehicles, such as bucket wheel excavators or mechanical shovels, are subject to maintenance or repair work as, for instance, repairs to the ring gear of the turntable of a mechanical shovel which require that the revolving frame thereof, i.e. the upper part of the mechanical shovel, be lifted so as to disengage the same from the shaft gudgeon which extends at right angle from the center of the ring gear of the carbody, i.e. the lower part or undercarriage of the mechanical shovel. Accordingly, in a conventional method for lifting the revolving frame of a given mechanical shovel, a number of short stroke jacks mounted on steel support members are first disposed at the rear and at the front of the aforementioned mechanical shovel and, more particularly, under opposite ends of the revolving frame thereof. After an initial extension of the short stroke jacks, wood blocks are disposed at the rear and at the front of the revolving frame to thus hold up in position the revolving frame while the short stroke jacks are retracted and mounted on other wood blocks for a second lifting operation. Due to the short stroke of the jacks, the overall lifting operation is made in several steps, i.e. in a series of successive short lifting operations, and requires continuous provision of wood blocks.
With this method, it takes up to six days for lifting and lowering a large mechanical shovel. Moreover, the operators must work under the load during the lifting operation and there is thus a significant risk of accident, for instance, because this method does not provide a high degree of stability (e.g. the wood blocks can sometimes yield or at least be crushed under the high load being lifted). It is also noted that for some specific models of mechanical shovels (less than 600 tons), a 150-ton crane was used to lift the front portion of the revolving frame with a pair of 200-ton jacks being used at its rear portion. Consequently, a great portion of space available in the workshop was taken by the crane which also was mobilized for a number of days.
Furthermore, the above method cannot be used outside of the workshop since it is not adapted to compensate for the packing soil effect which could occur at the lifting point during the lifting operation of such heavy mechanical shovels.
It is therefore an aim of the present invention to provide a lifting device and method adapted to ensure the safe lifting of heavy equipment, such as the mechanical shovels used in the mining industry.
It is also an aim of the present invention to provide a lifting device which is adapted to increase the speed of the lifting operation.
It is a further aim of the present invention to provide such a lifting device which is designed for offering ease of assembly and disassembly. It is a still further aim of the present invention to provide a shovel lifting device which is adapted for lifting different models of shovels.
It is a still further aim of the present invention to provide a shovel lifting device which is easy to transport.
It is a still further aim of the present invention to provide a lifting device which can be used in or outside of a workshop.
Therefore, in accordance with the present invention, there is provided a shovel lifting device comprising front and rear lifting beams which are adapted to support the revolving frame of a given mechanical shovel, front and rear lifting means respectively adapted to control the vertical displacement of said front and rear lifting beams, said front and rear lifting means, when taken as a whole, comprising at least three lifting means, and connection means interconnecting said front and said rear lifting beams with said corresponding lifting means, whereby said revolving frame of said mechanical shovel can be lifted by operation of said lifting means of said shovel lifting device.
Also in accordance with the present invention, there is provided a shovel lifting device comprising a front and a rear lifting beams, each said front and said rear lifting beams being provided with at least one bracket means which is adapted to cooperate with a mechanical shovel having an upper part and a lower part to ensure a proper positioning of said front and said rear lifting beams with respect to said mechanical shovel, front and rear lifting means adapted to control the vertical displacement of said front and said rear lifting beam, wherein said front and said rear lifting beam comprise at least three lifting means, whereby said upper part of the shovel can be lifted by operation of said lifting means of said shovel lifting device
Further in accordance with the present invention, there is provided a method of lifting heavy mechanical shovel using a shovel lifting device having front and rear lifting beam which are adapted to support the revolving frame of a given mechanical shovel, front and rear lifting means respectively adapted to control the vertical displacement of said front and rear lifting beam, wherein said front and rear lifting means, when taken as a whole, comprising at least three lifting means, the method comprising the following steps:
a) preparing a lifting area and the mechanical shovel;
b) installing said rear and said front lifting beams with said corresponding lifting means thereof at the appropriate location with respect to the mechanical shovel; and
c) lifting the mechanical shovel in a single step by operation of said lifting means.
Still further in accordance with the present invention, there is provided a method of lifting heavy mechanical shovel using a shovel lifting device having front and rear lifting beam which are adapted to support the revolving frame of a given mechanical shovel, front and rear lifting means respectively adapted to control the vertical displacement of said front and rear lifting beam, wherein said front and rear lifting means, when taken as a whole, comprising at least three lifting means, said lifting means being provided with detector means which are adapted to determine the length stroke and/or the absolute lifting elevation of the mechanical shovel at each of said lifting means, the method comprising the following steps:
a) preparing a lifting area and the mechanical shovel;
b) installing said rear and said front lifting beams with said corresponding lifting means thereof at the appropriate location with respect to the mechanical shovel;
c) mounting said detector means to said lifting means;
d) recording the reference lifting plan; and
e) lifting the mechanical shovel by operation of said lifting means.
Still further in accordance with the present invention, there is provided a method of lifting heavy mechanical shovel using a shovel lifting device comprising two lifting beams, removable bracket means being adapted to be mounted to said lifting beams, front and rear lifting means respectively adapted to control the vertical displacement of said front and rear lifting beam, said front and rear lifting means comprising at all at least three lifting means, said lifting means being provided with removable detector means which are adapted to determine the length stroke and/or the absolute lifting elevation of the mechanical shovel at each of said lifting means, the method comprising the following steps:
a) preparing a lifting area and the mechanical shovel;
b) if required, mounting said removable bracket means associated with the mechanical shovel to be lifted to said lifting beams;
c) installing said rear and said front lifting beams with said corresponding lifting means thereof at the appropriate location with respect of the mechanical shovel;
d) mounting said detector means to said lifting means;
e) recording the reference lifting plan; and
f) lifting the mechanical shovel by operation of said lifting means.